Abstract: A fluid delivery system includes a first chamber, a second chamber, and a third chamber, a pair of electrodes, a porous dielectric material, an electrokinetic fluid, and a flexible member including a gel between two diaphragms. The pair of electrodes is between the first chamber and the second chamber. The porous dielectric material is between the electrodes. The electrokinetic fluid is configured to flow through the porous dielectric material between the first and second chambers when a voltage is applied across the pair of electrodes. The flexible member fluidically separates the second chamber from the third chamber and is configured to deform into the third chamber when the electrokinetic fluid flows form the first chamber into the second chamber.

Abstract: The present invention provides a fluid delivery system having a first chamber, a second chamber and a third chamber; a flow-through pump element separating the first chamber from the second chamber; a moveable pump element separating the second chamber from the third chamber; a first outlet in communication with the third chamber; and second outlet in communication with the second chamber. Additionally, the present invention provides methods of operating a fluid delivery system having a first chamber, a second chamber and a delivery chamber by reducing the volume of the second chamber while increasing the volume of the delivery chamber without operation of a flow-through pump element that separates the second chamber from the first chamber.

Abstract: An electrokinetic pump achieves high and low flow rates without producing significant gaseous byproducts and without significant evolution of the pump fluid. A first feature of the pump is that the electrodes in the pump are capacitive with a capacitance of at least 10?4 Farads/cm2. A second feature of the pump is that it is configured to maximize the potential across the porous dielectric material. The pump can have either or both features.

Abstract: An electrokinetic pump and fluid delivery system is provided that may include any of a number of features. One feature of the fluid delivery system is that it can deliver a fixed volume of fluid with each stroke of the electrokinetic pump. Another feature of the fluid delivery system is that it can accurately deliver fluid at a target flow rate over time. Methods associated with use of the electrokinetic pump and fluid delivery system are also covered.

Abstract: An electrokinetic pump achieves high and low flow rates without producing significant gaseous byproducts and without significant evolution of the pump fluid. A first feature of the pump is that the electrodes in the pump are capacitive with a capacitance of at least 10?4 Farads/cm2. A second feature of the pump is that it is configured to maximize the potential across the porous dielectric material. The pump can have either or both features.

Abstract: One embodiment of the present invention provides a piston assembly having a piston housing filled with an electrolyte; a housing within the piston housing that divides the piston housing into a first portion and a second portion, the housing having apertures, a shaft connecting the housing to a piston head outside of the piston housing; and a porous material inside of the housing in contact with the electrolyte. Additionally, there are provided a method for filling the delivery chamber with a delivery fluid by withdrawing the piston head from within the delivery chamber. Yet another embodiment provides a method for filling a fluid delivery assembly by withdrawing a shaft from within the fluid delivery assembly to simultaneously displace a moving pump element within the delivery chamber and bypass fluid around a housing in the pump chamber.

Abstract: An electrokinetic pump achieves high and low flow rates without producing significant gaseous byproducts and without significant evolution of the pump fluid. A first feature of the pump is that the electrodes in the pump are capacitive with a capacitance of at least 10?4 Farads/cm2. A second feature of the pump is that it is configured to maximize the potential across the porous dielectric material. The pump can have either or both features.

Abstract: Electroosmotic flow controllers and methods of fluid flow control are described. The invention uses an electroosmotically generated flow component in conjunction with a pressure driven flow component to modulate fluid flow. The devices and methods of the invention may include salt bridges for making electrical connection between a power supply and a channel filled with a porous dielectric material and a fluid. Embodiments including flow controllers and flow splitters are described as is their use in a variety of fluid handling applications.

Abstract: Biochemical Assay Methods. There is described a method for determining a value that allows the effect that a compound has on a target to be compared with the effect that another compound has on the target, which method comprises adding the compound, at a concentration which continuously varies with time, to a flow of the target. The method can be carried out using a microfluidic system.

Abstract: A liquid sample is prepared at a preparation site and then processed, e.g. in an HPLC column. The sample is prepared and conveyed to the device at a flow rate which is substantially less than the flow rate through the device. The different flow rates are preferably provided by variable rate working fluid supplies which drive the sample from the preparation site and through the device.

Abstract: Microfluidic Systems, Devices and Methods for Reducing Diffusion and Compliance Effects at a Fluid Mixing Region. According to one embodiment, a microfluidic device is provided for combining fluids in a mixing region. The microfluidic device can include a fluid mixing region connected to a first and second microscale channel. The microscale channels can advance fluids to the fluid mixing region. The microscale channels can include constricted flow portions. According to another embodiment, the microscale channels can be connected to waste channels for removing fluid diffused into one of the channels from the other channel. According to yet another embodiment, a microfluidic system is provided for controlling the flow of fluids through the microscale channels for reducing or eliminating diffusion between the channels.

Abstract: A flow controller which uses a combination of hydrostatic pressure and electroosmotic flow to control the flow of a fluid. A driving fluid (1204) whose flow rate is dependent on both hydrostatic pressures and electroosmotic flow can be used (a) directly as a working fluid in an operable device, for example a chromatograph, or (b) to displace a working fluid (1203) from a storage container (625) into an operable device (1301), or both (a) and (b). The driving fluid (1204) can be composed of one or more fluids. Part or all the driving fluid (1204) is passed through an electroosmotic device (100) so as to increase or decrease the flow rate induced by hydrostatic pressure.

Abstract: One embodiment of the present invention provides a piston assembly having a piston housing filled with an electrolyte; a housing within the piston housing that divides the piston housing into a first portion and a second portion, the housing having apertures, a shaft connecting the housing to a piston head outside of the piston housing; and a porous material inside of the housing in contact with the electrolyte. Additionally, there are provided a method for filling the delivery chamber with a delivery fluid by withdrawing the piston head from within the delivery chamber. Yet another embodiment provides a method for filling a fluid delivery assembly by withdrawing a shaft from within the fluid delivery assembly to simultaneously displace a moving pump element within the delivery chamber and bypass fluid around a housing in the pump chamber.

Abstract: A method of treating a plastic surface with fluorine gas to decrease adsorption of hydrophobic solute molecules to the surface is provided. The method can include treating a surface with a first gas comprising fluorine gas and a second gas comprising oxygen gas, water vapor, or both oxygen gas and water vapor. Plastics treated using the method provide useful drug discovery and biochemical tools for the testing, handling, and storage of solutions containing low concentrations of hydrophobic solutes. Microfluidic devices containing treated plastic interior surfaces and methods of using such devices to make concentration-dependent measurements are also described.

Abstract: Microfluidic Chip Apparatuses, Systems, and Methods having Fluidic and Fiber Optic Interconnections. According to one embodiment, apparatuses and methods are provided for connecting a light-guiding conduit to a microfluidic channel. First and second substrates with first surfaces can be provided, wherein the first surfaces of the first and second substrates form a microfluidic channel and a connection channel when the first surfaces are positioned together, and wherein the connection channel extends from an edge of the first surface of the first or second substrate to the microfluidic channel. The apparatus and method can also include bonding the first surfaces of the first and second substrates to form the microfluidic channel and the connection channel.

Abstract: Methods for characterizing a biochemical reaction and analysis of reaction products by establishing continuously variable concentration gradients of one or more reagents of the biochemical reaction are provided. Methods for determining mechanism of inhibition or activation, potency of inhibition or activation, or both of an enzyme inhibitor or activator, respectively, are also provided. The continuously variable concentration gradients can be established in a microfluidic chip.

Abstract: Microfluidic methods and apparatuses for reducing the effects of sample adsorption inside microfluidic chann are provided. According to one embodiment, a microfluidic chip (MFC) comprising an analysis channel (AC) having a cross-sectional area at least two times larger than a cross-sectional area of a microscale channel in fluid communication with the analysis channel is provided that reduces the effects of compound adsorption on data analysis. According to another embodiment, methods for reducing the effect of molecule adsorption to a channel wall (W) on analysis of a reaction in a microfluidic device and methods for making concentration dependent measurements in a microfluidic device are provided which utilize novel microfluidic chips disclose herein.

Abstract: An actively temperature regulated microfluidic chip assembly includes a first thermally conductive body, a second thermally conductive body attached to the first thermally conductive body, a microfluidic chip encapsulated between the first and second thermally conductive bodies, and a temperature regulating element mounted to the first thermally conductive body for adding heat to or alternately removing heat from the chip. The temperature of the chip and thus the liquid contained and/or flowing therein can be regulated by measuring the temperature of the liquid and operating the temperature regulating element to establish a thermal gradient toward or alternately away from the liquid based on the measured temperature and in comparison with a desired set point temperature.

Abstract: According to one embodiment, an apparatus and method for delivering one or more fluids to a microfluidic channel is provided. A microfluidic channel is provided in communication with a first conduit for delivering fluids to the microfluidic channel. Further, the apparatus and method can include a first fluid freeze valve connected to the first conduit and operable to reduce the temperature of the first conduit for freezing fluid in the first conduit such that fluid is prevented from advancing through the first conduit.

Abstract: Methods and Apparatuses for Generating a Seal Between a Conduit and a Reservoir Well. According to one embodiment, an apparatus is provided for generating a seal between a conduit and a reservoir well. The apparatus can include a mount including a first and second end. The mount can also include a first aperture extending between the first and second ends. The apparatus can also include a tube including a first end engaging the first end of the mount, and operable to hold a conduit having an end such that the conduit extends through the first aperture of the mount and the end of the conduit communicates with a reservoir well. Further, the apparatus can include a nut operable to engage the mount and tube and seal the conduit to the first aperture of the mount such that air cannot communicate from the reservoir well through the first aperture of the mount.